We have presented 309 new white-dwarf ( WD ) + main-sequence ( MS ) star binaries identified from the Sloan Digital Sky Survey ( SDSS ) Tenth Data Release ( DR10 ) .
The majority of them consist of a white dwarf and a low-mass secondary ( typically M dwarf ) companion .
The SDSS spectra of the newly found WDMS binaries with a DA/DB white dwarf and an M/late-K dwarf companion are analyzed based on a spectral decomposition/fitting method .
White dwarf effective temperatures , surface gravities and masses together with the secondary star spectral types are obtained , and the stellar parameters of DA WDs with T _ { eff } \la 14 , 000 K are revised to the results in the case of 3D model atmosphere .
Two independent distance estimates are derived from the flux-scaling factors between the WDMS SDSS spectra and the white dwarf and M-dwarf model spectra .
It is found that about more than 20 per cent of the newly found WDMS binaries show a significant discrepancy between the two distance estimates .
This might be caused by the effects of M-dwarf stellar activity or irradiation of the M dwarf companions by the white dwarf .
The stellar parameter distributions are used to investigate the global properties of newly found WDMS binaries , the results shown in this work are consistent with those derived by previous investigators .
Some WDMS binaries have been observed more than one ( 2 - 4 ) times by SDSS , it is found that four of them exhibit not only Hydrogen emission in all observable Balmer series lines in addition to He I line Balmer lines but also the rapid variation in the radial velocities of the components in these binaries .
This suggests that they should be the post common envelope binaries ( PCEBs ) with a short orbital period .
These young PCEBs are very important for limiting the results of common envelope phase of the binary evolution .